> Source: [sk163353](https://support.checkpoint.com/results/sk/sk163353)

# sk163353 - "An unexpected error occurred" error message displayed when adding machines/users to a policy/deployment rule in SmartEndpoint

| Property | Value |
|----------|-------|
| Solution ID | sk163353 |
| Date Created | 2020-01-03 |
| Last Modified | 2020-01-07 |
| Technical Level | Advanced |
| Products | Endpoint Security |
| Versions | Cloud, E89.X, E88.X, R82.20, R82.10, R82, R81.20 |
| OS | Windows, Gaia |

## Symptoms

- * When adding a user or machine to a policy or deployment rule in SmartEndpoint, this error pops up, after policy installation. "An unexpected error occurred Sorry for the inconvenience, please restart the application." ![](https://sc1.checkpoint.com/sc//SolutionsStatics/NEW_SK_NOID1572592334860/Unexpected1911010034.PNG)

* In *%localappdata%\\CheckPoint\\SmartEndpoint_Logs\\R80_XX\\SmartEndpoint_Logs.txt* :   
  2019-08-02 18:29:20,329 \[Main Thread\] ERROR LogFileAppender --\>Exception: An unexpected error occurred --\>  
  --\>Exception: Object reference not set to an instance of an object.  
  --\> at GuiISWPF.ControlsLibrary.DataGridIconStringColumn.LoadContent(DataGridCell cell, Object dataItem, ContentPresenter cp)  
  at GuiISWPF.ControlsLibrary.DataGridIconStringColumn.GenerateElement(DataGridCell cell, Object dataItem)  
  at System.Windows.Controls.DataGridCell.BuildVisualTree()  
  at System.Windows.Controls.DataGridCell.OnIsEditingChanged(Boolean isEditing)  
  at System.Windows.Controls.DataGridCell.OnIsEditingChanged(Object sender, DependencyPropertyChangedEventArgs e)  
  at System.Windows.DependencyObject.OnPropertyChanged(DependencyPropertyChangedEventArgs e)  
  at System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e)  
  at System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)  
  at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry\& newEntry, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType)  
  at System.Windows.DependencyObject.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType, Boolean isInternal)

## Cause

Issue related to .NET framework.

## Solution

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